In general all commands for plotting data , have a
well defined syntax:
COMMAND/QUALIFIER P1 P2 P3 P4 P5 P6 P7 P8,
where:
P1 = table, image, descriptor or keyword name
P2 = columns, area, or indices of P1
P3 = scales in world coordinates/mm or size of the plot; only
for PLOT commands
The meanings of the remaining parameters on the command lines vary from
command to command; in most cases they are used for options.
Obviously, in case of overplotting , the parameter for the scales is
absent.